Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0035078 (renal failure)
 31,970 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The development of tubulointerstitial fibrosis in inflammatory renal diseases has been linked to disease progression to end-stage renal failure. Understanding the interactions of the factors influencing inflammation and activating the fibrotic process, that is, the inflammatory infiltrate and the resident proximal tubular cells, may lead to a determination of the mechanisms that regulate tubulointerstitial fibrosis. We used an in vitro model of human proximal tubule cells that were stimulated with supernatant from activated peripheral blood mononuclear cells (leukocytes) to study the alterations in cellular phenotype, and examined the signaling pathways mediating epithelial-fibroblast like transdifferentiation. Our hypothesis of the proposed sequence of events leading to tubulointerstitial fibrosis is explained.
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PMID:Factors produced by activated leukocytes alter renal epithelial cell differentiation. 1050 71

Dent's disease is an X-linked inherited disorder characterized by hypercalciuria, nephrocalcinosis, nephrolithiasis, low molecular weight proteinuria, Fanconi's syndrome, and renal failure. It is caused by inactivating mutations in CLC5, a member of the CLC voltage-gated chloride channel family. CLC5 is known to be expressed in the endosomal compartment of the renal proximal tubule, where it may be required for endosomal acidification and trafficking. Although the Fanconi's syndrome and low molecular weight proteinuria in Dent's disease can be explained by disruption of endosomal function in this nephron segment, the pathogenesis of the hypercalciuria in this disease is unknown. We have generated transgenic mice (RZ) with reduced CLC5 expression by introduction of an antisense ribozyme targeted against CLC5. RZ mice are markedly hypercalciuric compared with nontransgenic control mice, at a time when their serum electrolytes and renal function are otherwise normal. This suggests that hypercalciuria in Dent's disease is a direct consequence of CLC5 hypofunction and is not attributable to a gain of function by mutant CLC5, an effect of modifier genes, or a secondary result of nonspecific renal injury. Surprisingly, hypercalciuria in RZ mice is abolished by dietary calcium deprivation, suggesting that the hypercalciuria may be attributable to gastrointestinal hyperabsorption of calcium rather than a renal calcium leak.
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PMID:Diet-dependent hypercalciuria in transgenic mice with reduced CLC5 chloride channel expression. 1051 95

In the kidney, endothelins (ETs) are important regulators of blood flow, glomerular hemodynamics, and sodium and water homeostasis. They have been implicated in the pathophysiology of acute ischemic renal failure, nephrotoxicity by cyclosporine, cisplatin and radiocontrast agents, and vascular rejection of kidney transplants. Here, we used intact killifish renal proximal tubules, fluorescent substrates for Mrp2 (fluorescein-methotrexate, FL-MTX) and P-glycoprotein (a fluorescent CSA derivative, NBD-CSA), and confocal microscopy to reveal a new role for renal ET: regulation of ATP-driven drug transport in proximal tubule. Subnanomolar to nanomolar concentrations of ET-1 rapidly reduced the cell-to-tubular lumen transport of both fluorescent compounds. These effects were prevented by an ET(B) receptor antagonist but not by an ET(A) receptor antagonist. Immunostaining with an antibody to mammalian ET(B) receptors showed specific localization to the basolateral membrane of the fish tubular epithelial cells. ET-1 effects on transport were blocked by protein kinase C-selective inhibitors, implicating protein kinase C in ET-1 signaling. Finally, the nephrotoxic radiocontrast agent iohexol reduced cell-to-lumen FL-MTX and NBD-CSA transport, and these effects were abolished by an ET(B) receptor antagonist. These are the first results linking ET to the control of xenobiotic transport and the first demonstrating control of renal multidrug resistance-associated protein 2 and P-glycoprotein by a hormone.
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PMID:Endothelin B receptor-mediated regulation of ATP-driven drug secretion in renal proximal tubule. 1061 79

Heme oxygenase-1 (HO-1) is a 32-kDa microsomal enzyme that catalyzes the conversion of heme to biliverdin, releasing iron and carbon monoxide. Induction of HO-1 occurs as a protective response in cells/tissues exposed to a wide variety of oxidant stimuli. The chemotherapeutic effects of cis-diamminedichloroplatinum(II) (cisplatin), a commonly used anticancer drug, are limited by significant nephrotoxicity, which is characterized by varying degrees of renal tubular apoptosis and necrosis. The purpose of this study was to evaluate the functional significance of HO-1 expression in cisplatin-induced renal injury. Our studies demonstrate that transgenic mice deficient in HO-1 (-/-), develop more severe renal failure and have significantly greater renal injury compared with wild-type (+/+) mice treated with cisplatin. In vitro studies in human renal proximal tubule cells demonstrate that hemin, an inducer of HO-1, significantly attenuated cisplatin-induced apoptosis and necrosis, whereas inhibition of HO-1 enzyme activity reversed the cytoprotective effect. Overexpression of HO-1 resulted in a significant reduction in cisplatin-induced cytotoxicity. These studies provide a basis for future studies using targeted gene expression of HO-1 as a therapeutic and preventive modality in high-risk settings of acute renal failure.
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PMID:Heme oxygenase-1 gene ablation or expression modulates cisplatin-induced renal tubular apoptosis. 1080 84

The consumption of plants containing atractyloside, a diterpenoid glycoside, causes selective proximal tubule injury leading to renal failure and death in humans. The underlying mechanisms responsible for its toxicity are still not well understood. The present study was therefore carried out to determine the mechanism and the exact sequence of events that lead to molecular toxic injury. A comparative study using renal cortical slices, suspension of freshly isolated renal proximal tubular fragments and glomeruli of male Wistar rat was made. These in vitro systems were exposed to 100-1000 mM atractyloside for 2-3 h at 37 degrees C. Atractyloside caused a significant alteration in various toxicity parameters in a concentration- and time-dependent manner in renal cortical slices and proximal tubular fragments, but not in glomeruli. The earliest change following exposure to atractyloside (1000 microM) was a significant reduction of intracellular adenosine 5'-triphosphate (ATP) content occurring within 1 h in the tubules and 2 h in slices. The significant depletion of reduced glutathione (GSH) inhibitor of p-aminohippuric (acid) (PAH) uptake and gluconeogenesis occurred simultaneously following loss of cellular energy. These events were only limited to the renal cortical slices and proximal tubular fragments. Increased severity of cellular injury resulted in cytotoxicity with the significant increase in the leakage of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in proximal tubular fragments (occurring at 2 h) and renal cortical slices (occurring at 3 h). There were, however, no alterations in oxidized glutathione (GSSG) levels or in the ratio of GSH/GSSG. Only limited lipid peroxidation in proximal tubular fragments and glomeruli was observed at atractyloside concentrations of 500 microM and above. In all cases of toxicity, the glomeruli were unaffected. Pretreatment of slices or fragments with probenecid (1.0 mM) failed to completely abolish atractyloside toxicity. These data demonstrate dose- and time-dependent toxicity of atractyloside and clearly confirmed the proximal tubular fragments as the target tissue. Atractyloside exhibits a toxicity profile that indicates early alteration in mitochondrial function and consequently loss of cellular energy, followed by reduced metabolic function and transport processes and ultimately cell death. This appears to be the most likely mechanism by which atractyloside exerted its acute cytotoxicity. Renal cortical slices, which maintain proximal tubule and glomeruli in their anatomic relationship, responded similarly to atractyloside toxicity as the proximal tubular fragments, and might be suggested as the most suitable in vitro model system for studying the mechanisms of atractyloside toxicity as they are more likely to mirror changes seen in the whole organ.
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PMID:Atractyloside nephrotoxicity: in vitro studies with suspensions of rat renal fragments and precision-cut cortical slices. 1090 Apr 5

Autosomal recessive polycystic kidney disease (ARPKD) is a rare but devastating inherited disease in humans. Various strains of mice that are homozygous for the cpk gene display renal pathology similar to that seen in human ARPKD. The PKD progresses to renal insufficiency, azotemia, and ultimately a uremic death by approximately 3 wk of age. This study characterizes PKD in mice that are homozygous for the cpk gene on a BALB/c inbred mouse background. The BALB/c-cpk/cpk murine model displays renal as well as extrarenal pathology similar to that found in human ARPKD. The renal pathology includes the well-characterized early proximal tubule and, later, massive collecting duct cysts. The extrarenal defects in this murine model include common bile duct dilation, intrahepatic biliary duct cysts with periductal hyperplasia, and pancreatic dysplasia with cysts. Renal mRNA expression of c-myc, a proto-oncogene, and clusterin (SGP-2), a marker associated with immature collecting ducts, decreases during normal development but is upregulated in murine ARPKD. Expression of epidermal growth factor (EGF) mRNA is significantly diminished, whereas EGF receptor mRNA is upregulated in the BALB/c-cpk/cpk kidney compared with phenotypically normal littermates. To determine whether the altered EGF expression contributes to the development of PKD, neonatal mice were treated with exogenous EGF (1 microg/g body wt injected subcutaneously on postnatal days 3 through 9). EGF treatment reduced the relative kidney weight and common bile duct dilation and downregulated renal expression of clusterin and EGF receptor. However, exogenous EGF did not affect the degree of renal failure, the pancreatic pathology, or the misregulated renal expression of c-myc. In summary, the present study characterizes the renal and extrarenal pathology in the BALB/c-cpk/cpk murine model of ARPKD. Renal mRNA expression of EGF is diminished in this mouse model. EGF treatment did not prevent renal failure but ameliorated pathologic changes in the kidney and the biliary ducts of the BALB/c-cpk/cpk mouse.
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PMID:Development of autosomal recessive polycystic kidney disease in BALB/c-cpk/cpk mice. 1100 14

Sucrose nephropathy was first described more than 50 years ago. The disorder is characterized by acute renal failure caused by the uptake of sucrose by renal proximal tubule cells with subsequent cellular swelling and occlusion of the tubule lumen. Approximately 114 cases of renal failure have been associated with high-dose intravenous immune globulin (IVIG) therapy. Almost all cases were caused by preparations containing large amounts of sucrose. Clinicians should consider using IVIG preparations containing no sucrose in patients who are at high risk for renal failure. Risk factors include older age, baseline renal failure, and volume contraction.
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PMID:Reemergence of sucrose nephropathy: acute renal failure caused by high-dose intravenous immune globulin therapy. 1100 52

Renal failure by bee venom may be related to a malfunction of renal transporters. However, the effects of bee venom on apical membrane transporters of renal proximal tubular cells are not yet known. The aim of this study was to examine the effects of dried bee venom of Apis mellifera and its melittin on apical transporter activity of primary cultured rabbit kidney proximal tubule cells. Bee venom (1 microg/ml) decreased the cell viability and increased lactate dehydrogenase activity over 30-min treatments. Its effect was blocked by mepacrine or AACOCF(3) (10(-6) M; phospholipase A(2) inhibitors). However, there was no effect on cell viability at a concentration of 0.01 microg/ml of bee venom. Thus, we investigated the effect of bee venom (1 microg/ml) on the activity of renal transporters at 30 min. Bee venom inhibited alpha-methyl-D-glucopyranoside, Pi, and Na(+) uptakes, but increased Ca(2+) uptake. These effects of bee venom were blocked by mepacrine or AACOCF(3) (10(-6) M), and bee venom-induced stimulation of Ca(2+) uptake was also blocked by methoxyverapamil and nifedipine (L-type calcium channel blockers). In addition, bee venom increased [(3)H]-arachidonic acid release by 216 % of that of control. In all experiments, bee venom melittin (0.5 microg/ml) had an identical effect to that of bee venom itself. In conclusion, bee venom inhibited, in part, alpha-MG, Pi, and Na(+) uptakes through its melittin which increased Ca(2+) uptake and arachidonic acid release in primary cultured rabbit renal proximal tubule cells.
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PMID:Effect of bee venom and its melittin on apical transporters of renal proximal tubule cells. 1107 Apr 19

Chronic renal failure is characterized by diminished synthesis of, and resistance to, the active vitamin D metabolite 1,25-dihydroxy-vitamin D3 (1,25(OH)2D3, calcitriol). Calcitriol results from the biotransformation of the precursor 25-hydroxy-vitamin D3 (25(OH)D3) to 1,25(OH)2D3. 25(OH)D3 is synthesized in the liver, and 1alpha-hydroxylase, the rate-limiting enzyme for its biotransformation into the most active metabolite, 1,25(OH)2D3, is located in the kidney. The regulation of 1alpha-hydroxylase in renal failure is not well known. Recent work indicates that, in contrast to previous opinion, 1alpha-hydroxylase is predominantly expressed not in the proximal tubule but in the distal tubule [1]. In vivo, the main stimulatory signal is presumably parathyroid hormone (PTH) and the main inhibitory signal hyperphosphataemia. Both signals are altered in renal failure. There is also evidence that the renal 1alpha-hydroxylase becomes substrate-dependent in patients with renal failure. This means that a higher concentration of the precursor 25(OH)2D3 will result in a higher rate of transformation into the active metabolite 1,25(OH)2D3 in renal patients. Calcitriol is not exclusively synthesized in the kidney, but may also be synthesized in extra-renal tissues, e.g. activated monocytes/macrophages [2], particularly in granuloma [3] as shown by anephric uraemic patients who develop hypercalcaemia and elevated calcitriol concentrations when sarcoidosis [4] or tuberculosis [5] supervenes. On the other hand, calcitriol is less effective in uraemia. This may be to some extent due to diminished expression of vitamin D receptors [6], particularly in parathyroid glands when they undergo nodular transformation [7], but there may also be resistance to calcitriol at the post-receptor level [8]. In a series of elegant experiments [9,10], calcitriol resistance has been related to disturbed genomic effects of active vitamin D because the interaction of the vitamin D receptor ligand complex with vitamin D-responsive elements (VDREs) upstream of vitamin D-regulated genes was disturbed by the action of low molecular weight substances in uraemia, which have not been completely characterized. The role of genetically determined polymorphisms of the vitamin D receptor in the genesis of disturbed calcium metabolism of renal failure is currently unclear.
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PMID:Management of disturbed calcium metabolism in uraemic patients: 1. Use of vitamin D metabolites. 1107 70

Cyclosporine (CsA) treatment in solid organ transplantation has represented one of the greatest advances in the past 20 years, reducing acute rejection and increasing long-term survival. However, CsA has an important side effect, producing renal vasoconstriction and systemic hypertension. The main histological findings in the kidney are vascular lesions in the endothelium and smooth muscle cells. On proximal tubule cells, severe atrophy, vacuolization and thickening of the basal membrane can be found. The main mechanisms of vasoconstriction are secondary to endothelium disorders, increasing vasoconstrictor substances like endothelin, thromboxane, free radicals, etc., and reducing vasodilator substances like nitric oxide and prostaglandins. CsA acute nephrotoxicity produces haemodynamic changes with minor histological lesions, which will disappear when the medication is discontinued. Long-term CsA nephrotoxicity has been widely discussed in the literature. For some authors, a limited number of patients can develop end-state renal failure but others did not suffer these complications. Nevertheless, it seems clear that high doses of CsA can produce renal lesion and renal insufficiency, being difficult to evaluate in renal transplant patients because of the frequent association with chronic rejection lesions. Several types of drugs have been used to treat CsA nephrotoxicity in renal transplant patients but calcium antagonists and angiotensin converting enzyme-inhibitors are the most frequently used, especially the former due to their effect on the afferent arteriole vasodilatation, their natriuretic properties and their reducing intracellular calcium. The greatest experience has been with nifedipine, but other drugs like verapamil, diltiazem, amlodipine, felodipine, isradipine, etc., have also been used. Lacidipine, a 1,4-dihydropiridine, has demonstrated a beneficial effect during the short term after renal transplantation, and a multicentre, multinational, double-bind, placebo-controlled clinical trial for the long term currently ongoing.
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PMID:Calcium antagonists and renal protection from cyclosporine nephrotoxicity: long-term trial in renal transplantation patients. 1134 60


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